RULE BREAKER UPPER- FOUND MATERIALS
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If you are a serious runner, or even if it is just a hobby, there is a good chance that the hot summer months don’t stop you from trying to get out and get running. Not only is track and field a spring competition sport, meet and public 5k, half marathons and marathons take place year round. Especially in certain parts of the world this can be some serious heat.
Data show us that the body’s response to rising temperatures is non-linear, meaning the performance will get exponentially worse moving from 70 to 90° F as compared to 50 and 70° F.
When running in thees temperatures, your organs and working muscles compete for a limited blood supply, which compromises the body’s natural cooling system. Humidity compounds the problem, by hindering the evaporation of sweat, making it harder to cool yourself. This leads athletes who are performing intense exercise in hot weather tend to become dehydrated. “With less water in the body, you have less blood plasma volume—the liquid portion of your blood—to serve all your needs.” (Hanc, J. (2019)
One writer for runners world pushed through a hot Dallas half marathon explaining that when weighing himself at the end of the race he had lost nearly four pounds. “That’s a 2.3 percent body-mass loss—anything more than two percent will affect your running,”.
While humidity compounds the issue by reducing sweats ability to evaporate, in a study of army training it was found that in dry heat, the peak oxygen consumption the soldiers were able to achieve was 5.7% lower than their maximal oxygen consumption in comfortable conditions.
When designing an upper for running it is important to understand the movements in the joints for this particular motion. Running is going to have increased joint flexion in comparison to walking, but much linearity than a sport like soccer. (Dugan, S.A., & Bhat, K.P. (2005). Understanding the areas of the foot with the highest degrees of bending can help me simplify an upper to areas that need flexibility vs areas that can be stable on the foot.
This study called “Intrinsic foot motion measured in vivo during barefoot running” from the Journal of Biomechanics displays data on relative motion of individual foot segments. The 3-D measurements were taken in vive with the use of reflective marker arrays attached to pins inserted in the tibia, talus, calcaneus, cuboid and navicular. Data were collected using a 10-camera optoelectric system (Qualysis, Sweden).
(Arndt, A., 2006).
While that encompasses very specific bones in the foot and rotation from multiple planes, to break it down:
(Prior, T. (n.d.). Foot anatomy.)
The forefoot undergoes the most motion with the forward bend. But it is also important to consider the mid-foot, specifically the navicular and its slight rotation as the foot joint arch increases. The heel also undergoes rotation relative to the rest of the foot as a natural running motion takes place. (Windsor, 2014).
This movement is crucial to consider as it is found that restricting intrinsic motion of the foot could result in non-physiological stresses on specific foot bones or sites such as the ankle ligaments.
When assessing the affect of heat on the body, I felt it important to look at the localized area on the body as well, the foot. The core temperature of the foot can play a role in the blood circulation and blood build if in the veins. Hot weather causes the blood vessels to dilate, so blood moves into the hands or legs by gravity. The extreme exercise coupled with heat vasodilation creates increases in capillary pressure. (Henry, J. P., & Gauer, O. H. (1950). All of these factors can contribute to a production of heat edema, a cutaneous condition characterized by vasodilatory blood pooling. The result is swollen feet and improper oxygen transport to the feet and toes. (Edema. 2017).
The best way to combat this is through hydration of the body and decreased localized core temperature of the foot which can helped through easier sweat evaporation from the upper.
When looking at preferred foot temperatures as a baseline it was found that while men and women have quite different lower and upper limits of foot temperature they they perceive as comfortable.
(Ciuha, U., & Mekjavic, I. (2017).
Over all average preferred temperature: TR: 18.7 ± 18.4 °C
Feet TR | Male 15.7 C | Female 19.4 C |
Feet TR | Male 26.2 C | Female 32.4 C |
While this is important to understand, the ability to perceive these temperatures can be inconsistent. In terms of perception, what I did find through my research though is the importance of perception of temperature and comfort. (Barkley, R, 2011).
Perceived temperature of the foot plays a huge role in whether or not a shoe is successful. I felt that this is especially important to consider when a shoe would be worn in strenuous hot exercise. In a study done by Heel Luxe, this difference in perceived comfort and actual foot temperature increases were measured.
During my upper design I am going to take the shoe a direction that has keeping the foot cool at the core of its design. When addressing what can make a shoe cooler, materiality is key but I really want to take in to consideration how heat is best removed from the skin. This can be by processes of evaporation, convection, radiation and conduction. For these to happen, molecules in the air must bump against the hot (fast moving) molecules of the skin, so that some of that heat energy can be transferred from to the passing molecules. After they’ve made contact, the air molecules must move away, carrying what was our body heat with them in the form of quickly moving. (Wolchover, N. (2012). This is why a fan is so helpful, and why when sweating while running a breeze on the face feels so cool as it assists evaporative cooling. This same effect can be better produced on the foot if more of the skin is directly available to the air.
When moving forward with design I felt it important to first understand what makes a good fitting shoe, including areas that need to hug the foot vs areas that need room to breath. Heel Luxe offered a great guide to optimal shoe fit based on assessments of hundreds of shoes and perceived comfort.
I felt that this diagram was easy to understand, and counter intuitive to what I assumed about shoe fit. The areas I will focus on for fit of my upper is securing through the navicular, and tops of the toes but leaving room for movement on the lateral phalangeal joint and sides of the heel. (The Secret Ingredient for Step In Comfort at Retail. (2020).
After digesting all of this information, I am excited to move forward pushing how minimal I could make a running upper. When I think of hot weather and having more skin exposed to passing air, I think of sandals. The sandal market is rather saturated with a few companies really capitalizing on the active, moving, outdoor user. Teva is one company that has been known for their sandals versatile to the outdoors.
The goal of sandals with strapping configurations similar to this is to provide the best securement to the foot. Keeping the heel and shoe in contact is critical to avoid the toes curling and clenching the sandal that we see in flip flops. This extra, unnatural work would be critical to avoid in running.
This nylon linear straps around the foot that outdoor brands use lock around foot bones, however they create pressure points at where the bone sticks out the farthest as opposed to conforming with the bone. Areas where the foot has the highest flexibility wrapping around a strap can dig in at the peripherals of the strap. This is why for lower joint movements with less frequency like walking and hiking these solutions could work, but not for running.
Some other inspiration that related to the sneaker work is the sandal like aesthetics of these sportswear shoes nike has released. It is pushing the idea of a sneaker upper form, but lacking the functionality.
These styles are good inspiration for pushing for a minimal fabric upper but I feel can be pushed farther and taken into the performance world.
Description: A convertible article of footwear has an upper outer component with a reversible exterior shell, an inner sandal base and means for repeatedly connecting and disconnecting these two main components to one another with either outer shell exposed.
This was a very basic early concept of what a shoe combined with a sandal could look like. The functionality and aesthetic are questionable but I liked where there head was at!
Description:
An X-strap assembly for securing an article of footwear to the instep of a foot, said footwear having a sole and channel through said sole, said X-strap assembly comprising: a strap attached at its respective ends to medial and lateral heel sides of said footwear, said strap having a first portion extending in a forward direction transversely across the instep from a first side of said footwear to a second side, a second portion extending through said channel, and a third portion extending in a rearward direction transversely across the instep from said first side to said second side of said footwear.
This is the kind of system that I see with a lot of the out door shoes with a variation of the strap going through a tunnel in the sole which I thought was interesting.
Description: A shoe construction employs straps formed of plastic material whereby separate areas of the shoe straps have different characteristics of elasticity, flexibility and rigidity. The construction of the strap provides areas connected to the shoe with greater elasticity and flexibility characteristics and a lesser rigidity characteristic than a second area of the strap that has greater rigidity characteristics and is connected to closure members of the shoe.
What I like about this concept is the variable flexibility of the straps which I feel works more naturally with how the foot moves over the course of the step.
Description: The present invention employs chimneys and chimneys structures to move or vent heat and moisture away from the foot and out of the microclimate of the shoe. The chimneys define pathways that utilize convection and other principles to cool and dry the foot.
This concept by Timberland I felt was an innovative way to cool the foot while still having it covered and protected which is needed for their user. This way of cooling can be useful inspiration.
Description: The means for exposing front portion of foot is the open or exposed area of the means for covering top of shoe, which exposes some, a portion, or all of the toes, and may include an additional indentation to expose some or all of the pinkie toe as well.
What I liked when finding this design was that their problem realted to the problem I am solving and added to it. Their design expalined how during extended periods of walking and/or running blisters, chafing, athlete’s foot, and the loss of toe nails are common. This is because an individuals toes, and/or front portion areas of their foot are rubbing against the inside portion of the top or side areas of the upper.
Moving forward with this project I am to create an incredibly minimal upper for a running shoe. The straps that hold the foot in place to keep the heel locked down and foot in the shoe will have variable flexibility and conform to curvature of the foot bones for the most natural fit. The result will be a shoe that does not look like any other running shoe, pushes the boundaries and exposes skin to get the highest evaporative and conductive cooling possible.
Chochrek, E. (2018, August 11). Nike Transformed Its Iconic Air Huarache Into a Gladiator Sandal. Retrieved from https://footwearnews.com/2017/focus/athletic-outdoor/nike-air-huarache-sandal-400130/
https://patents.google.com/patent/US20150000160?oq=sneaker+sandal
https://patents.google.com/patent/US6606803?oq=shoe+strapping
https://patents.google.com/patent/US5497564?oq=shoe+strapping
https://patents.google.com/patent/US8146266B2/en?q=keeping+foot+cool&oq=keeping+foot+cool
https://patents.google.com/patent/US20010025438A1/en?q=breathable+upper+running+shoe&oq=breathable+upper+running+shoe
Barkley, R., Bumgarner, M., Poss, E., & Senchina, D. (2011). Physiological Versus Perceived Foot Temperature, and Perceived Comfort, during Treadmill Running in Shoes and Socks of Various Constructions. Volume 10, Issue 3 American Journal of Undergraduate Research, 10(3). doi: 10.33697/ajur.2011.019
Henry, J. P., & Gauer, O. H. (1950). The Influence Of Temperature Upon Venous Pressure In The Foot. Journal of Clinical Investigation, 29(7), 855–861. doi: 10.1172/jci102318
Edema. (2017, October 26). Retrieved from https://www.mayoclinic.org/diseases-conditions/edema/symptoms-causes/syc-20366493#dialogId47296892
Ciuha, U., & Mekjavic, I. (2017). Thermal comfort zone of the hands, feet and head in males and females. Physiology & Behavior, 179, 427-433
Windsor, Williams, Songning Zhang, Dedrick, & Powell. (2014). High- compared to low-arched athletes exhibit longer foot-ankle moment arms during level running. 46(5), 809-809.
Hanc, J. (2019, June 11). The Heat is On. Retrieved from https://www.runnersworld.com/training/a20807061/the-heat-is-on/
Dugan, S.A., & Bhat, K.P. (2005). Biomechanics and analysis of running gait. Physical medicine and rehabilitation clinics of North America, 16 3, 603-21 .
The Secret Ingredient for Step In Comfort at Retail. (2020, March 25). Retrieved from https://www.heeluxe.com/the-secret-ingredient-for-step-in-comfort-at-retail/
Wolchover, N. (2012, July 9). Why Does a Breeze Feel Cool? Retrieved from https://www.livescience.com/34062-breeze-feel-cool.html
Arndt, A., Wolf, P., Nester, C., Liu, A., Jones, R., Howard, D., … Lundberg, A. (2006). Intrinsic foot motion measured in vivo during barefoot running. Journal of Biomechanics, 39. doi: 10.1016/s0021-9290(06)83644-4
Prior, T. (n.d.). Foot anatomy. Retrieved from https://www.timeoutdoors.com/expert-advice/running/footcare/foot-anatomy
To make my prototype I first cut a 3”x 3” square of the felt pad to get the base of my cushioning system. I had some 3/8” acoustic felt paneling, so this is what I used for the prototype but in the actual system the felt pad should be made from alpaca fibers and dense, but just soft enough to contribute to attenuation.
Next, I created the transparent tubes from a foggy transparent vinyl that I had. I cut each pice to be 3”x3” and sewed the tube using white thread. While this was the only type of material I had that could resemble what I was going for, ideally if manufactured, to stay eco friendly could use a recycled material or a look alike made form cellulosic materials.
Using alpaca fibers cut from an old alpaca seat cushion I stuffed the tube to a desired fill amount. I then repeated this process with the two other tubes.
The amount of fiber fill and how it interacts with the felt pad underneath is is what is giving the impact attenuation. The fill amount and felt pad density would need to be thoroughly tested to determine the best options. With my design idea, the amount of fill could vary per tube giving a zoned support structure to areas of the foot that will create higher forces. The tubes also do not need to be linear but could also curve along the foot natural shape. Diagram of peak force locations on the foot during stride shown blow.
Next I needed to finish the sides and glue all of the pieces together. In manufacturing, the tubes could be closed objects in their own that may not need side finishing. I felt that it would be a cool feature to see these natural fiber shoes. I also thought that a rubber dip that wraps around the sides of the tubes to show their shape could be cool too. However, with building this prototype I knew it needed to be finished off so I stuck with a more solid material using an open cell foam that visually resembled a recycled rubber material. I cut thin strips 3” long.
The final step was gluing all of the elements together.
When tasked to create a cushioning system for a performance shoe, I first wanted to hone in on what type of athlete I wanted to serve. In my life I have done a lot of sports, but I was never the best on the team in any of them. I am a strong believer in sport as a hobby to keep a healthy, happy life. Running is one of the most accessible sports in the world because you don’t need a designated field, rink or equipment. However, not everyone can be the Usain Bolt, Allyson Felix, or Eliud Kipchoge of running.
Motivating people to want to be a better version of themselves is not hard, but actually getting them to do it is. The best way to get someone to do something and make a habit of it is creating positive memories of the activity. Designing a cushioning system to create an experience, evoke positive feelings and store those feelings to memory with the goal of getting the individual running more often.
The first thing that I wanted to address when starting the research on this topic was what are the unique characteristics of an untrained runner vs. a trained runner that I would need to take into consideration when designing the shoe.
The common theme among untrained runners is a low running cadence. This is the number of strides you take per minute. When running, one wants to spend the least amount of time on their legs as possible. Inexperienced runners are taking longer for each stride. (Hutchinson, A., 2019)
In a study of 10 randomly selected trained and untrained athletes published in the The Journal of Strength and Conditioning Research this difference was observed.
The more time each foot spends on the ground surface, the more energy the legs have to use to support the body weight. Additionally it means that the the amount of force during the contact with the ground is going to have lower peak forces because it is spread out over a longer period fo time. While this is not efficient is it important to take into consideration when in the design phase.
Other factors that are critical to understand when designing for these users are directly related to this. 37-56% of untrained runners suffer from at least one injury each year. Usually, there are four stages of a running stride: initial contact, braking and absorption, mid stance, and propulsion. (Gomez, Josue & Ogueta-Alday, 2017). If a runner wants to achieve a balanced and pain-free stride all four have to be done correctly.
Since I am designing a cushioning system the phase that I can primarily impact is the braking/absorption phase of running: According to The Motion Analysis Laboratory at University of Montana: When the foot collapses, or pronates, and the leg bends, your body controls the effect of the shock caused by gravity on the joints. After absorbing the impact, your legs can begin to move you forward.
The in-expeierenced runner, on average is over extending their stride, putting their first contact with the ground farther back on their heel with their foot farther in front of them. This is called over-striding, and is a major cause of both hamstring and knee injuries. The most efficient running stride involves the use of the core muscles for propulsion and not the lower legs, more experienced runners tend to have their feet landing closer beneath their center of gravity. (Van Mechelen, 1992).
It is important to note that when a runner is running their stride can change significantly. No matter if you are a top marathon athlete or are going out for your first run the stride length and where your foot is striking can alter after fatigue. The point of fatigue for a recreational runner will occur much sooner and a cushioning system must account for the variance in strike and forces. (Novacheck, Tom F, 1998).
Going into this cushioning task I first started with getting inspiration of softening impact through an egg drop. The design idea used only alpaca fur and rubber bands. Alpaca was wrapped around the egg and stayed in place by rubber bands. The drop was successful and can be viewed in the video link below. While the idea originated from a bag of Alpaca fur I happened to have lying around the house (very random I know!) I was inspired to see what the world of cushioning could looked like if natural fibers were utilized over EVA Foams.
While there are a lot of sneakers that boast sustainable materials these days there were very few that had an innovative renewable midsole.
Recycled bottles has become a common Eco Friendly option for large shoe giants like Nike and Adidas midsoles but it is still not renewable. The Reebok shoe uses a corn based sole which is an exciting direction, but still does not utilize natural fibers.
While these shoes may not be the most optimized for elite athletes, I feel going in this direction for the recreational runner that isn’t looking at their energy return is important. This is because if we can make a running shoe for the largest running population sustainable it will have the biggest of impacts for the environment.
Opportunities I potentially see using natural fibers in cushioning is in their resiliency, texture, and felting abilities. When searching for patents I did find some that were exploring directions with natural fibers which I think could be exciting to use as inspiration and build from.
A system for creating an alpaca bonded fiber pad. The pad is used for bedding products, cushions, toppers and furniture. The system includes an alpaca fiber washing station for cleaning and processing the fiber and a pad forming machine.
This is a system for creating Alpaca pads that they have patented but it gives good insight to processes that could be derived from when in the creation of my cushioning system.
Now that I addressed many of the physical design factors I would need to take into consideration, I need to look at creating a relationship with cushioning and the brain.
Ultimately I felt I first needed to understand what evokes a pleasurable recollection of an event in a human. Memory is an often inaccurate, subjective function of the brain. What we remember, how we remember and when we remember are extremely complex factors that phycologists are constantly studying. What studies have shown us is that events that are either very positive or very negative are the most likely to stay in our memory.
As Brown and Kulik (1977) noted in their seminal paper on “flashbulb memories,” “events of emotional significance are more likely to be recalled vividly than mundane experiences, and neurobiological research has confirmed that the occurrence of affective responses can increase the likelihood that an event is stored in memory.” (Holland, A.C. & Kensinger, E.A. (2010). When a person is running, they may feel severe discomfort and fatigue. During a run they may have passed a pretty view or felt proud of them selves but for most people, the severe negative can be what their lasting memory of their running experience is after the fact. This is due to the polarizing effect of the affect (emotion) experienced. (Brown, R.. & Kulik, J. (1977))
While utilizing affective responses to influence memory it is important to understand that it is not enhancing the memory, it is creating a trade off. The memory works in such a way that enhancing memory for select features of an event will often impairing memory for other aspects. This is exactly what I want to do.
My goal is to create a feeling, whether emotional or physical that can become a stronger influence in their memory creation than physical fatigue they feel during their run. That way when the user processes if they want to go out for a run or not, the prior experience they are pulling from in their brain to inform the decision is over ridden by a positive affect and not their level fatigue.
Haptic memory is the type of sensory memory specific to touch stimuli. When the skin is in contact with an object touch is impacted by the form and the surface texture. According to Hatch Interior Designs: “texture can be described as either tactile or visual. Tactile texture relates to the actual feeling of a surface – smooth, rough, soft, hard, etc.”
The reason that I decided to look into touch is because touch is considered a “contact sensory modality” as compared to distal senses such as vision and audition. This sensory system provides information through direct contact with our body. Inside of a shoe, where the foot has contact to what is beneath it the only sense at play is touch.
Touch is considered to be one of the most arousing senses (Etzi, R., & Gallace, A. (2016)., but according to research, its role in driving emotional evaluations (which leads to memory creation) is often underestimated. Touch has a long history in the evolution of humans and primates. Interpersonal touch, for example, is key for the psycho-physical well-being and social bonding in both species.
Based on biological evolution, reactions to tactile stimuli should be quick and fast, given that once a stimulus is on the skin surface there is not much time to make predictions on its nature or threatening value (Association for Psychological Science. (2018.). However, not all stimuli is a danger. The foot is a glabrous body area, meaning with out hair. on these parts of the body touch is created through A{beta} fibers that known to be a class of fast conducting nerves. Just as quickly as a foot could sense pain, it can feel pleasure.
According to findings published in Psychological Science, a journal of the Association for Psychological Science, exploring objects through touch can generate both detailed and durable memories. Even when, in many cases we don’t intend to memorize the object’s details.
There are several offers both on the market and through product patents that are dealing with foot stimuli. Many of these products look at recovery through insoles or sandals. While these products are good examples of a direction I can draw from, none are robust enough to be worn during running, nor focus on renewable materials, or high peak forces.
The first product I found was the:
This product boasts the following features:
This brand also offers this technology in sandals and slides to be worn at the end of a work out or day on your feet. The idea of reaching the foots pressure points is a good direction but the nodes would be too much for high impact over a long period of time.
Patents in this area:
“Pieces of apparel, such as foot-receiving devices (e.g., shoes, socks, or the like), form systems and perform methods for applying stimulus to at least a portion of a subject’s body to dynamically and/or reflexively affect the subject’s performance, motion, orientation, balance, timing, or the like.”
This patent by Nike Inc Covers stimuli for performance of mechanical sort. They were applying things like mechanical pressure, temperatures and vibrations to enhance footwear athletic performance. I am not using a mechanical stimuli but the inspiration of where on the foot stimuli may be effective is helpful.
The Nike Joyride. A shoe designed to be a fun running experience for the every day runner. And yes, this sounds very much like what I am trying to do!
It doesn’t take very long searching on the internet to reveal how polarizing this cushioning technology is. There’s people who absolutely hate it, and others that enjoy it quite a lot.
Joyride Run Flyknit works through four pouches of free flowing foam beads beneath each foot. In each shoe there can be up to 9,000 beads. The beads conform to your foot when putting the shoe on, trying to mimics if you were stepping on a bean bag. The idea being that the shoes are a customized cushioning system for whoever the user is. (Whitcomb, D., & Whitcomb, D. (2020.) This idea of customization of the cushioning form is where I feel Joyride’s technology is strong.
What I do not feel is strong is the joy part of the ride. Visually, the beads remind me of a ball pit that I would play in as a kid. This subconscious connection of these visuals can be strong, but based off of my research, not as strong is if it was a haptic connection. Ultimately, my goal is to get the person running regularly, not just enjoy the sensation once once or to buy a shoe because it visually reminds you of your childhood.
My goal is to get people who are not trained runners, running regularly. The biggest hurdle is one’s own motivation due to unpleasant physical perception because the person is simply out of shape. By utilizing the mind’s unconscious memory creation of haptic experiences I want to create a pleasant sensory response to the midsole of the shoe. The purpose of this is creating a trade off of what gets stored in the memory. When designing I know that I need to take into consideration the improper running form of new runners with a longer stride, as well as the sustainability of a shoe that is being massed produced. I am going to move forward with alpaca fibers, which provided great cushioning in my egg drop experiment. I feel that through my research moving forward to ideation and prototyping I can achieve perception of enjoyment after the run is done, which is what is needed to get the person to lace back up and go on that next run.
Chayne, K. (2019, April 17). 7 Eco-friendly Sneakers You Can Actually Get Active In. Retrieved from https://consciousfashion.co/guides/eco-friendly-sneakers-running-shoeshttps://patents.google.com/patent/US20150208752?oq=alpaca+cushioning
https://patents.google.com/patent/US9527227?oq=alpaca+cushion
https://patents.google.com/patent/US6978684B2/enq=foot+stimuli&oq=foot+stimuli
https://patents.google.com/patent/US20150239208?oq=alpaca+foam
https://patents.google.com/patent/US20030200675A1/en
Kenkoh Insole Natural Massage Insole. (n.d.). Retrieved from https://www.happyfeet.com//Products/Kenkoh-Insole-Natural-Massage-Insole__3803-NAT.aspx?gclid=CjwKCAjwg6b0BRBMEiwANd1_SHtejuSxhExapaFUpBqyJ-iSWQJdMQWfdmpmJe_cjeXpslLhY7UTWRoCcRYQAvD_BwE
Whitcomb, D., & Whitcomb, D. (2020, January 22). Nike Joyride Run Flyknit Performance Review. Retrieved from https://weartesters.com/nike-joyride-run-flyknit-performance-review/
Brown, R.. & Kulik, J. (1977) Flashbulb memories. Cognition, 5, 73-99.
Holland, A.C. & Kensinger, E.A. (2010). Emotion and autobiographical memory. Physics of Life Review, 7, 88-131.
Association for Psychological Science. (2018, November 27). Touch can produce detailed, lasting memories. ScienceDaily. Retrieved April 5, 2020 from www.sciencedaily.com/releases/2018/11/181127092532.htm
Etzi, R., & Gallace, A. (2016). The arousing power of everyday materials: an analysis of the physiological and behavioral responses to visually and tactually presented textures. Experimental Brain Research, 234(6), 1659+. Retrieved from https://link-gale-com.libproxy.uoregon.edu/apps/doc/A451018284/AONE?u=euge94201&sid=AONE&xid=76139337
Randl, C. (2010). Sensuality and shag carpeting: a design review of a postwar floor covering. The Senses and Society, 5(2), 244+. Retrieved from https://link-gale-com.libproxy.uoregon.edu/apps/doc/A235721606/AONE?u=euge94201&sid=AONE&xid=da6b3273
Running Foot Strike: Proper Running Technique for Your Feet [Guide]. (2019, May 6). Retrieved from https://www.roadrunnersports.com/blog/running-foot-strike/
10 Components of Proper Running Form. (2018, September 28). Retrieved from https://www.chirunning.com/blog/10-components-of-good-running-form/
Hutchinson, A. (2018, July 28). Lessons from Watching the World’s Best Runners. Retrieved from https://www.outsideonline.com/2329876/iaaf-biomechanics-study-worlds-best-runners
Novacheck, Tom F. The Biomechanics of Running. Gait & Posture. 1998;7(1):77-95. doi:10.1016/s0966-6362(97)00038-6.
Van Mechelen, W. (1992). Running Injuries. Sports Medicine, 14(5), 320–335. doi:10.2165/00007256-199214050-00004
Gomez, Josue & Ogueta-Alday, Ana & Stickley, Christopher & Tobalina, Jesús & Cabrejas-Ugartondo, Jon & Garcia-Lopez, Juan. (2017). Differences in Spatiotemporal Parameters Between Trained Runners and Untrained Participants. Journal of Strength and Conditioning Research. 31. 2169–2175. 10.1519/JSC.0000000000001679.